Finned tube heat transfer unit with control guides



FINNED TUBE HEAT'TRANSFER UNIT WITH CONTROLGUIDES Filed June 1, 1966 i I in "ml" n,

United States Patent 3,386,501 FINNED TUBE HEAT TRANSFER UNIT WITH CONTROL GUIDES Michael W. Pastore, Hartford, Conn., assignor to Argo Industries, Incorporated, Hartford, Conn., a corporation of Connecticut Filed June 1, 1966, Ser. No. 554,375 Claims. (Cl. 165-82) ABSTRACT OF THE DISCLOSURE A finned t-ube heating unit having plastic strip control guides along the corners. Each fin includes two dovetail notches in each side edge, one near the top, and the other near the bottom, of the fin. Each plastic strip has an E-shaped cross section. Two legs of the E extend into a notch in each fin, the remaining leg extends beyond the respective top or bottom edge of each fin.

This invention relates to finned tube heat transfer units and, more particularly, to such units having improved fin control guides.

A very common application of finned tube heat transfer units is the well known baseboard radiator. In these installations, the fins are customarily of sheet metal cut into rectangular shapes and the assembly rests on suitable hangers. Certain problems are presented by these units which the prior art has attempted to overcome with only partial success. Many of these problems arise from the requirement that provision be made for expansion and contraction of the heat transfer unit as it is heated and cooled. If the hanger is assumed to be fixed, then suitable provision must be made for movement of the finned tube-preferably with a minimum of noise. Also, some strengthening of the assembly .is desirable as is protection of the installing workmans hands from the sharp corners of the fins.

One approach which has been taken by the prior art in an attempt to solve the above problems has been the installation of guides running along the aligned corners of the fins. These guides are of metal or plastic and have either an arc-uate or an angular cross section. The edges of the guides extend inwardly into notches which are formed in adjacent edges of each fin and equidistant from a corner of the fin.

While it is true that the prior art devices achieve certain of their objectives, they also create other problems which it would be desirable to alleviate. One of these problems is that a great part of the convection area is closed by the guides. This is due to the fact that each guide extends across the top or bottom edge of a fin for the same distance it extends along a side. Another disadvantage is that the fins themselves must be formed with eight different notches, two in each of the four sides. It would be desirable to reduce the number of notches required and thus simplify the construction of the unit.

Accordingly, it is a primary object of the present invention to provide an improved heat transfer unit of the finned type. Other objects are to provide such a heat transfer unit which includes guide elements for expansion and contraction; wherein the guide elements create minimum blocking of convection currents; and wherein notching of adjacent edges of the individual fins is not required.

The manner in which the foregoing objects are achieved will be more apparent from the following description, the appended claims and the figures of the attached drawing wherein:

FIG. 1 is a front view of a baseboard radiator incorporating this invention, portions thereof being broken away to illustrate the internal construction;

FIG. 2 is a cross section taken substantially along the line 22 of FIG. 1;

FIG. 3 is an enlarged detail of the fin and guide assemy;

FIG. 4 is a perspective view of a portion of a guide strip; and

FIG. 5 is a front view, on a reduced scale, of a baseboard radiator incorporating this invention.

The objects of this invention are achieved by means of a heat transfer unit which comprises a plurality of hanger means and an elongated fluid conductive tube. A plurality of rectangular metal fins are secured to the tube in heat conductive relationship at longitudinally spaced intervals and extend radially therefrom. Each of the fins has top and bottom edges and first and second side edges. Each side edge defines at least one notch. First and second elongated fin control guides engage, respectively, the notches in the first and second side edges only. Each of the fin control guides further includes a portion which extends beyond the bottom edge and is positioned on the hanger.

With particular reference to FIGS. 1 and 2 there is illustrated a baseboard radiator incorporating the present invention. The radiator includes a vertical mounting plate 10 which is mounted against a wall at its junction with the floor. The mounting plate is formed with vertically aligned pockets 12, 14 at spaced intervals along its length. Each pair of pockets supports a hanger 16, by means of tabs 18, 20 which extend from the top and bottom ends of the flat hanger body 22. The hanger body is formed with a pair of aligned, parallel ridges 23. The hanger is formed with an upper support arm 24 and a lower bracket arm 26. The upper support arm 24 and the lower bracket arm 26 are formed in such a manner as to support therebetween a front housing 28. In addition, the upper support arm 24 includes a hinge tab 29 for hingedly supporting a damper member 30. While it will be obvious that the lower bracket arm 26 could be formed to support the improved finned tube assembly of the invention, in the disclosed embodiment the arm is modified by means of an adapter 32. The adapter is in the form of a metallic strip which is spot welded to the bracket arm to define a rear support surface 34, a forward support surface 36, and a forward retaining tab 38.

The finned tube assembly of the invention includes a copper tube 40 upon which are mounted thin aluminum fins 42. Each fin is secured to the copper tube in the usual manner by means of a central opening surrounded by a flange 44. The fins are rectangular and each is provided, along each side edge only, with a pair of dovetail notches 46.

Mounted along each corner of the finned tube assembly is a fin control guide 48. Four identical control guides are used in the illustrated assembly and an enlarged detail of one is shown in FIG. 4. The guides may be made of any suitable material but are preferably extruded in strip form from a plastic such as polypropylene. The guide is essentially a plastic strip having an E-shaped cross section resulting from a flat body portion 50, a central web member 52, and edge web members 54. The central web member 52 terminates in a head 56 of substantially circular cross section. Each of the edge web members 54 is angled slightly outwardly relative to the body portion 50 and terminates in an inwardly extending head 58. The body portion need not be perfectly fiat but may be curved.

The control guides 48 are snapped into position in the aligned notches 46 of the finned tube assembly as shown in FIG. 3. Each of the notches 46 is so proportioned that adjacent the side edge of a fin 42 it is narrower than the outer dimension between the central head 56 and either of the outer beads 58. The natural resiliency of the webs permits their insertion into the notches 46 and retains the guide in its illustrated position. When so installed, it will be noted that, while two of the webs and their associated beads retain the control guide within the notches, the remaining web 54 is positioned against the top or bottom edge of each fin 42. In this manner they serve to increase the rigidity of the structure, act as bearing spacers, and serve as guards for the sharp corners of the fins. More importantly, there is practically no blockage of vertically rising convection air currents. For example, in an actual embodiment of this invention, the maximum vertical dimension of control guide 48, measured across the outside of beads 58, is .46 inch. The maximum horizontal dimension from the outer surface of body portion 50 to the terminal edges of the beads is .12 inch.

It will also be noted that the lower head 58 encompassing each of the two lower corners of the assembly rests respectively upon the forward support surface 36 and the rear support surface 34 of each of the hanger adapters. These smooth, relatively low friction, surfaces permit noiseless longitudinal sliding to allow for expansion and contraction of the assembly. In addition, the dimensional relationships are such that the back surfaces of the control guides along the wall edges of the fins rest against the ridges 23 of the hanger body 22 while the control guide 48 at the lower outermost corner of the assembly bears against the retaining tab 38 of each hanger adapter. Thus, the fin tube assembly is rendered substantially vibrationless as a further aid in reducing noise.

Although a specific embodiment of this invention has been described and illustrated herein, it will be understood by those skilled in the art that a number of variations and modifications may be made in the invention without departing from its spirit and scope, Accordingly, the foregoing description is to be construed as illustrative only, rather than limiting. This invention is limited only by the scope of the following claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A heat transfer unit which comprises: a plurality of hanger means; an elongated fiuid conductive tube; a plurality of rectangular metal fins secured to said tube in heat conductive relationship thereto at longitudinally spaced intervals therealong and extending radially therefrom, each of said fins having top and bottom edges and first and second side edges, each side edge defining at least one notch solely contained therein and spaced from said bottom edge; and first and second elongated fin control guides each including a support portion engaging, respectively, the notches in said first and second side edges only, each of said fin control guides further including a. bearing portion extending around the bottom corners of said fins and positioned on said hanger means.

2. The unit of claim 1 wherein each of said control guides comprises: an elongated body portion; a central web member integral with said body portion and extending outwardly from, and substantially perpendicular to, a first side thereof; and first and second edge web members integral with saidbody portion and extending outwardly from said first side, said central web member and said first edge web member being adapted to be engaged by one notch in each of said fins.

3. The unit of claim 2 wherein each of said central and edge web members terminates in a bead.

4. The unit of claim 2 wherein each of said notches is a dovetail notch.

5. The unit of claim 2 wherein said bearing portion includes said second edge web member.

6. The unit of claim 1 wherein each side edge defines an upper and a lower notch positioned, respectively, adjacent an upper and a lower corner of said fin.

7. The unit of claim 1 wherein said hanger means includes support surface means supporting said bearing portions.

8. The unit of claim 1 wherein each of said hanger means includes laterally spaced, first and second vertical retaining means engaging, respectively, said first and second fin control guides.

9. The unit of claim 1 wherein said fin control guides are plastic.

10. The unit of claim 9 wherein said plastic is polypropylene.

References Cited UNITED STATES PATENTS 2,963,276 12/1960 Nelson 55 X 3,258,066 6/1966 Becher et al 16555 3,263,746 8/1966 Becher et a1 165-55 ROBERT A. OLEARY, Primary Examiner.

A. W. DAVIS, Assistant Examiner. 

